Reversible heat pump system



Sept. 27, 1966 D. H. SNIADER 3,275,067

REVERSIBLE HEAT PUMP SYSTEM Filed Nov. 5, 1963 United States Patent C) 3,275,067 7 REVERSIBLE HEAT PUB/ll SYSTEM David H. Sniader, 1225 Spruce St., Winnetka, Ill. Filed Nov. 5, 1963, Ser'. No. 321,627 6 Claims. (Cl. 165-29) This invention relates to thermostatically controlled heat pumps which operate reversibly to heat or cool room air. More in particular this invention relates to an air conditioner operable thermostatically to cool a room and alternately to heat a room under the control of a thermostat.

In conventional water-cooled air-conditioning systems the water, during the warm season, enters the condenser somewhere between 60-85 F. and discharges approximately 25 F. above inlet temperature. If the same air conditioner is operated in reverse cycle the heat pump then delivers heat to the room which heat is extracted from the condenser water. In such operation the water discharging from the condenser is about 25 F. below the inlet water temperature. Now during the winter months, particularly in northern areas such as Chicago, Illinois, water temperatures often drop to 35-38? F. Since during heat pump cycle operation the system extracts heat from the flowing condenser water, unless a high flow rate of condenser water is employed'the heat extracted would result in freezing of the Water in the condenser. Once freezing of the water in the condenser occurs no further water flow is possible and thus the heat pump could no longer extract heat. I I p V In order to overcome the above described difliculties it is a prime object of the present invention toprovide means for controlling the temperature of the inlet water to the condenser during operation on heat pump cycle.

Another important object of the invention is to provide an auxiliary water coil adjacent the evaporator coil for the purpose of augmenting the function of the evaporator coil.

Still another important object of the invention is to pro-.

vide means for automatically elevating the temperature of inlet water to the condenser during heat pum opera: tion.

A yet further object of the present invention is to pro- These and other important objects inherent in the inaugment a heat pump. vide means for employing a central hot water source to ven'tion will be more readily understood from preferred embodiments of the invention described in the ensuing description, the appendedclaims, and the annexed drawings wherein:

FIGURE 1 is a schematic drawing illustrating a reversible cycle heat pump with automatic means for elevating the temperature of the Water. entering the condenser according to this invention;

FIGURE 2 is another form of the invention which interposes an auxiliary water coil adjacent the evaporator which further increases the efficiency of the system; and

FIGURE 3 is a variation of the system of FIGURE 2 wherein the auxiliary water coil employs a secondary source of hot water.

With continued reference to the drawings the numeral 5 in FIGURE 1 indicates an electrically energized refrigerant gas compressor of conventional construction. The compressor 5 discharges liquified compressed refrigerating Patented Sept. 27, 1966 gas through line 6 to an electrically opearted reverse cycle valve 7 of conventional design. When the system is operated for cooling a room or rooms (i.e., air conditioning) the reversing valve 7 comunicates line 6 with port 9 of water medium heat exchanger .or condenser 10 through line 8. The liquified compressed refrigerant is cooled by the water condenser 10 and discharges as cooled liquified compressed refrigerant through port 11 of condenser 10 and enters a conventional strainer 13 through line 12. From the strainer 13 the cooled liquified compressed refrigerant passes through line 14 to evaporator indicated at 15 through the orifice 16 thereof. As the cooled liquified compressed refrigerant passes through orifice 16 of evaporator 15 a large pressure drop occurs so that the liquid refrigerant vaporizes to the gas phase thereby lowering the temperature of the gasdue to absorption of heat. The cold gas flows through the coil 17 of the evaporator 15 which absorbs heat from room air driven thereacross by a conventional electric fan (not shown). The refrigerant gas with heat thus absorbed from the room is conducted to an accumulator 18 as indicated in FIGURE 1. From accumulator 18 the refrigerant gas communicates with the inlet side of compressor 5 through line 19, reverse cycle valve 7, and line 20..

The relief valve 21 is interposed between lines 6 and 20 to prevent excessive pressure being developed by the compressor 5, I

During room cooling cycle (air conditioning) just de-v Thus the temperature in line 23 is elevated from that of the inlet water at port 22. v

Now when the above described system is operated in reverse cycle the reverse cycle valve 7 connects line 6 with line 19 and thus the hot liquified refrigerant being discharged from the compressor Sis conducted into the evaporator coil 15 which heat is discharged into the room by the room air circulating fan (not shown) moving the room air across the coil 17. In effect this removes heat from the liquified refrigerant thus heating the room. The thus cooled liquified refrigerant passes through orifice 16 into line 14, strainer 13, line 12 and into the condenser unit 10 through line 11. Between the orifice 16 and.

port 11 the pressure drop causes the liquified refrigerant to vaporize which results in a sharp temperature drop as is well known. The inlet water entering the port 22 of condenser 10 is thus cooled and the temperature of the inlet water is sharply reduced (usually about 25 F.) in the drain line 23.

It will -be appreciated from the above that during reverse cycle operation for heating the room theevaporator 15 actually functions as a heat exchanger in the same manner as the condenser 10 during room cooling cycle. But for simplicity in description the unit 10 will be referred to as a condenser andthe unit 15 will be referred to as an evaporator although both are heat exchangers.

Up to this point a conventional reversible cycle heat pump has been described which may be operated for cooling a room when the temperature of the room is above a predetermined upper limit and reverses to deliver heat in the even-t the temperature of the room air is below .a lower predetermined limit. Conventional thermostatic valve 7 and energizing the compressor 5 are employed.

The water pump 24 is merely a conventional means for removing condensate water from the collecting tray 25 which is condensed from the room air during room cooling cycle operation.

The prime novel feature of the present invention resides in the combination of water heating means with the above described reversible heat pump whereby water entering the port 22 of condenser is thermostatically controlled to a predetermined minimum temperature during heat cycle Operation. This is accomplished by interposing a thermostatically controlled water heater 26 in the inlet water line 27 from a primary source of cooled water. The conventional heater 26 may heaLthe Water by electrically heated elements, gas or other means. Thus, during the colder months when the inlet water source enter.- ing line 27 reaches a predetermined minimum temperature, say 70 F., the heater functions to heat the inlet water temperature. If desired the thermostat of the water heater may be electrically interconnected with the room thermostat so that'when heat is called for the ther mostat control of the water heater 26 is energizedwhen the room thermostat energizes the reverse cycle valve 7 to room heating cycle. The inlet water temperature at port 22 of condenser 10 is thus controlled to a predetermined minimum. From this it becomes apparent that during winter months operation on heat cycle, the water in the condenser 10 will not freeze. Further, the water heater 26 provides the system with a source of heat which heat is'transferred from the condenser 10 to the evaporator 15.

In order to prevent unnecessary flow of water through the condenser 10 during periods when the system is not operating, i.e., when the room temperature thermostat is satisfied and thus neither calls 'for heating nor cooling, a conventional valve system, generally indicated at 28, is employed. Valve 29 is interposed between inlet water condenser 10. However, when the system is operating on room heating cycle thepressure in ,line 8 is low and 4 h 27. In this arrangement part of the heat absorbed by Y the room air is furnished directly by the water heater thus valve 29 remains closed. In order to provide water the reverse cycle valve 7 is energized to shift to the heat cycle operation position.

FIGURE 2 is a modification of the above described 1 system. In essence it prow'des a secondary coil indicated at 35 positioned adjacent the evaporator coil 15' wherein the coil 35 is connected in series relation with the water heater 26 and condenser unit 10. Thus inlet water entering line 27 .during cooling cycle operation passes through pressure operated valve 29 into line 36, through coil35 and thence into port 22 of condenser '10 through line 37. Since, during warm months; inlet water temperature 27 is usually well below room temperature, the coil "35 functions to absorb some'heatfrom the room and yet remain sufliciently cool to function'for further heat absorbing in the condenser unit 10. In this arrangement the hot water heater 26 is interposed in the by-pass system 28. Thus during roomheating cycle inlet water from line 27 passes through line 32, energized solenoid valve 34, through line 33, hot water heater 26 to line 36 through line 38. From this it is apparent that hot water from heater 26 is conducted directly to the secondary coil35 through line 36 wherein some of the heat from the hot water is absorbed directly into the room fromcoil 35 and adrition-al heat is extracted from the hot water y the, condenser unit 10 before discharge to .drain line:

' tion of said system for heating said room, and a secondary 26 and the balance of heat is furnished indirectly, through the heat pump heating cycle operation.

The modification shown in FIGURE 3 is similar to that'shown in FIGURE 2 except that the secondary coil 35' is connected to a central hot water source, such source being common inhotels and apartment buildings. The central hot water source enters through line ,39, shut-01f valve 40 which may be of a solenoid typeenergized under thermostat control, and line 41. The discharge flow may be discharged to drain through line 42 as shown in FIGURE 3. or alternately connected to flow through the condenser 10 as shown in FIGURE :2.

In generalthe capacity of a heat. pump system is chosen for cooling a room to a temperature of a few lower capacity heat pumps and yet provide sufficient heat. when outside temperatures are extremely low.- On the.

other hand the system of FIGURE 1 is quite adequate where outside temperatures seldom are below 50 F. Of course, if an adequate capacity heat pump is used sufficient to heat thevroom adequately when outside temperatures are extremely low then, the secondary coil 35 or 35' would be unnecessary.

. Having thus described preferred embodiments of the invention it can be seen that the objects of the inventon have been fully achieved and it must be understood that I modifications thereof may be made which do not depart trom the spirit of the invention nor from the scope thereof as defined in the appended claims.

What is claimed is:. 1. A heat pump system for selectively heating and cooling aroom comprising, in vcombination,,a refrigerant compressor, a reverse cycle valve, an evaporator coil. for selectively heating and cooling .the .air within said. room and a heat exchanger connected in operative rela-I tion, said exchanger including a water medium heat. ex-- change means, and a water heating means. communicatively connecting a source. of cooled water to the inlet side i of the water medium heat exchange means for'heating,

said water only during operation of said system for heating said room, and a secondaryco'il positioned adjacent, to said evaporator coil, said secondary coil being inter-' posed in. series relation between the discharge side of said water heating means and the said'inlet side of said heat exchanger whereby said secondary coil is heated. by said water heating means. only during operation of said system for heating said room.

2. A heat pump system according to claim l wherein,

said water heating means is thermostatically controlled. 3..A;heat pump system forselectively ,heating. and

cooling a room comprisingiin combination, a refrigerant compressor, a reversecyclevalve, an evaporator coil'disposed within said room and a heat exchanger connected 'in operative relation, said exch-anger'including a water" medium heat exchanger means, and a water heating means communicatively connecting a primary source of cooled water to the inlet side of said water medium heat exchange rneansfor heating said water only during operacoil positioned adjacent said evaporator coil, said secondary coil being connected serially to the water inlet side; of said heat exchanger and to the discharge side of said water heating means and said primary source, and valvemeans for connecting said primary source of water with said secondary coil'during operationof said system tor cooling said -room and. alternately connecting said water heating means in series relation with said secondary coil during operation of said system for heating said room.

4. The invention according to claim 1 and means including valve means for bypassing said water heating means during the room cooling cycle of the system.

5. The invention according to claim 4 and means for thermostatically controlling the heating of said water heating means.

6. The invention according to claim 4 and said valve means being of a pressure operated type, and means for connecting the valve means to one side of the heat exchanger for response to the pressures at the heat exchanger.

References Cited by the Examiner UNITED STATES PATENTS 2,260,887 10/1941 Dasher 165-62 X 2,441,885 5/1948 Kemler et a1. 62-16O 2,484,371 10/1949 Bayston 62-324 X 10 ROBERT A. OLEARY, Primary Examiner.

C. SUKALO, Assistant Examiner. 

1. A HEAT PUMP SYSTEM FOR SELECTIVELY HEATING AND COOLING A ROOM COMPRISING, IN COMBINATION, A REFRIGERANT COMPRESSOR, A REVERSE CYCLE VALVE, AN EVAPORATOR COIL FOR SELECTIVELY HEATING AND COOLING THE AIR WITHIN SAID ROOM AND A HEAT EXCHANGER CONNECTED IN OPERATIVE RELATION, SAID EXCHANGER INCLUDING A WATER MEDIUM COMMUNICATIVECHARGE MEANS, AND A WATER HEATING MEANS COMMUNICATIVELY CONNECTING A SOURCE OF COOLED WATER TO THE INLET SIDE OF THE WATER MEDIUM HEAT EXCHANGE MEANS FOR HEATING SAID WATER ONLY DURING OPERATION OF SAID SYSTEM FOR HEATING SAID ROOM, AND A SECONDARY COIL POSITIONED ADJACENT TO SAID EVAPORATOR COIL, SAID SECONDARY COIL HEATING INTERPOSED IN SERIES RELATION BETWEEN THE DISCHARGE SIDE OF SAID WATER HEATING MEANS AND THE SAID INLET SIDE OF SAID HEAT EXCHANGER WHEREBY SAID SECONDARY COIL IS HEATED BY SAID WATER HEATING MEANS ONLY DURING OPERATION OF SAID SYSTEM FOR HEATING SAID ROOM. 